Sheet metal nibbler construction



Jan. 10, 1961 1. J. YERMISH SHEET METAL NIBBLER CONSTRUCTION Filed Dec. 30, 1959 26 5+ gtml 52 16 f 0 Fl 6 m% 2m l #8 Ill 4 i Q s 4 w n 8\ 1|: 1 I: L A 5 0 G 4 2855 7 4. 3

INVENTQR ISRHEL Q. YER MISH BYA/ ATTORNEY United States Patent SHEET METAL NIBBLER CONSTRUCTION Israel J. Yermish, Philadelphia, Pa., assignor to Feuway Machine Company, Inc., Philadelphia, Pa., a corporation of Pennsylvania Filed Dec. 30, 1959, Ser. No. 862,916

7 Claims. (Cl. 30-228) This invention relates generally to an improved construction of portable hand held sheet metal cutting tools of the nibbler type, and in particular relates to an improvement in the construction of the nibbler punch and punch-holding ram assembly.

In the past, experience has shown that there exists a tendency for the punch to be stripped out of the punch holding ram on the non-cutting upstroke when heavy gauge metal stock is being cut. This occurs because the punch end is firmly grasped by the cut edges of the metal stock which exert a holding pressure thereon of greater magnitude than that exerted by the side pressure exerting set screw means normally employed to secure the punch within the ram. Consequently, the ram retracts but the punch does not and the nibbler is rendered inoperative for further cutting. A typical punch and ram construction of this type is shown and described in United States Patent No. 2,827,696 assigned to the same assignee as the instant application, the present invention being an improvement thereof.

A principal object of the invention is, therefore, to provide a novel nibbling tool punch which is securable within the ram in such fashion as to prevent the punch from being stripped out of the ram under any operating condition.

Another object of the invention is to provide a novel nibbling tool punch which is positionally vertically adjustable within the ram and which is positively securable therein in any adjusted position.

Still another object of the invention is to provide a novel non-strippable positionally adjustable punch which may be directly substituted for the presently known type generally employed in tools already in use.

Other objects and advantages of the present invention will appear more fully hereinafter, it being understood that the invention consists substantially in the construction, combination, location and relative arrangement of parts, all as described in the accompanying drawings and as finally pointed out in the appended claims.

In the accompanying drawings:

Figure 1 is a view looking at one side of a tool constructed in accordance with and embodying the principles of the present invention, a portion being in elevation and a portion in vertical section;

Figure2 is a section on line 2-2 of Figure 1;

Figure 3 is an enlarged fragmentary view of the punch assembly according to the invention disposed within the ram, as illustrated in Figure 1, some parts being shown in section and others in elevation; and

Figure 4 is an enlarged exploded view of the punch assembly illustrated in Figure 3, some parts being shown in section and other parts in elevation.

In the several figures, like elements are denoted by like reference characters.

Referring to Figures 1 and 2 of the drawings, the nibbler tool constructed in accordance with and embodying the principles of the present invention is provided with a body designated 10, a head designated 11 that is mounted upon the body 10 in axial extension thereof, and a nose designated 12 that extends laterally from the head 11. Normally the body 10 and head 11 extend horizontally, and the nose 12 depends therefrom.

The body 10 houses an electric motor (not shown) that is supplied with power through the medium of a cable 13, the electric motor being controlled by the operator through finger pressure applied to a switch control lever 14 that is mounted upon a handle 15. The body 10 and head 11 are internally provided with means, presently to be described, for translating the rotary motion of the electric motor into reciprocating motion of a punch generally designated 16, the latter being operatively mounted in the nose 12.

The nose 12 is a cylindrical part that is provided with an external flange 17 which is located intermediate the opposite ends thereof. One end portion of the nose 12 is projected into the head 11 from the underside of the latter, and the nose 12 is secured to the head 11 through the medium of the flange 17. The lower terminal portion of the nose 12 is tapered to a blunt tip, as indicated in Figure 2. The nose 12 is provided with a central through bore that has an upper section designated 18 and a lower communicating section of reduced diameter designated 19.

The means aforesaid for translating rotary motion of the electric motor into reciprocating motion of the punch 16 comprises a generally cylindrical plunger or ram 26 that is provided with a main body part 27 which terminates at its upper end in a head part 28 of enlarged diameter and flattened on the fore and aft sides thereof to provide a pair of parallel surfaces, respectively designated 29 and 30, spaced apart a distance corresponding to the diameter of the main body part 27.

Referring particularly to Figures 2 and 3, the ram 26 is generally of T-shape in longitudinal section, the stem or main body part 27 being slidably fitted into, and the head part 28 being disposed in superposed spaced relation to the upper end portion of the nose part 12. Extending transversely through the head part 28 is a rectangular opening 31 that is defined by horizontally extending upper and lower walls designated respectively 32 and 33 and vertically extending opposite end walls designated respectively 34 and 35.

Extending through the ram 26 is a central bore that has upper, intermediate and lower sections designated respectively 36, 37 and 38. These bore sections are of successively decreasing diameter, and the intermediate section 37 is internally threaded. The larger diameter bore section 36 communicates, intermediate the opposite ends thereof, with the rectangular opening 31,

Referring now particularly to Figures-3 and 4, disposed within the threaded intermediate section 37 of the ram 26 is an open-ended cylindrical hollow bushing exteriorly and interiorly threaded as at 71 and 72 respectively. The exterior bushing threads 71 permit the entire bushing to be screwed upwards and downwards within the ram by means of the screw driver slots 73 cut downward into the bushing walls at the top end thereof. Recessed into the exterior of the bushing wall is an insert 74 of nylon or similar material which frictionally engages the threads of the ram intermediate portion 37 to secure the bushing against undesired movement due to vibration when the tool is in operation. The insert is, of course, conformingly cut by the threads 37 when first screwed into the ram, and while resisting vibratory movement of the bushing does not prevent 21 of the punch 16, the undersurface of the radially enlarged punch head 39 seating upon the bushing inturned annular bottom flange 75. The punch 16 is thus vertically adjustable in accordance with the adjusted position of the bushing 70. The punch shank 21 is essen tially round in cross-section except for the flattened face 22 and the rectangular lower cutting blade portion 20. A set screw 76, exteriorly threaded as at 77 and having a flattened bottom 78 and socketed top 79, is threaded into the bushing 70 and screwed down tightly until the bottom 78 seats upon the punch head 39. The punch head 39 is thus clamped between the set screw bottom surface 78 and the bushing annular bottom flange 75 so that the punch 16 is locked to the bushing 70. Since the bushing 70 is fixed in an adjusted position relative to the ram 26, the punch 16 is also so fixed and is constrained to move with the ram. The bushing bottom flange 75 and punch head 39 prevent the punch from being stripped out of the ram during the upstroke, and the set screw 76 acts as a punch backing during the power stroke. Threaded through the wall of the ram 26, on the fore side thereof, and projecting respectively into the lowe and intermediate bore sections for engaging the flat surface 22 of the punch shank 21 are a pair of set screws 40 and 41 operative to secure the punch 16 against chatter during operation thereof by clamping the shank against the wall surface of the ram lower section central bore 38.

A lower end portion of the punch 16 is slidably received in the reduced diameter bore 19 of the nose part 12 for guidance thereby. For guiding the punch blade 20, the nibbler tool is provided with a guide 23 of generally T-shape in vertical transverse section suitably fitted into and secured to the back of the nose part 12, and with a die plate 24 that is carried by the guide 23. In addition, the tool is provided With a stripper member 25 that is suitably fitted into the lower terminal portion of the nose part 12. If desired, reference may be had to United States Patent No. 2,844,872 assigned to the same assignee as the instant invention, for a more detailed description of the guide member 23, die plate 24 and stripper 25, and for a more detailed description of the manner of the assembly thereof with the nose part 12 and punch 16.

The head 11 of the tool is provided with a hollow casing section that has on the underside thereof a wall 42. The upper end portion of the nose 12 is projected through, and the flange 17 is secured to this wall 42. Integral with the latter are upright transversely extending fore and aft walls designated respectively 43 and 44, and longitudinally extending opposite side walls designated respectively 45 and 46. The top of this casing section is provided with an access opening designated 47 and a removable closure member designated 48.

The means aforesaid for translating rotary motion of the electric motor into reciprocating motion of the punch 16 additionally comprises a pair of ball bearing units, designated 49-49, respectively mounted in the transversely extending casing walls 43 and 44. Journalled in these units are concentric opposite end portions, respectively designated 50 and 51, of a shaft that is projected through the ram head 28. The intermediate portion of the shaft aforesaid, designated 52, is eccentrically disposed relative to the opposite end shaft portions 50 and 51 and is revolubly extended through a central aperture 53 formed in a slide block 54, which latter is mounted in the head 28 for shifting movement from side to side within the rectangular opening 31. The shaft portion 51 is operatively connected with the electric motor through the medium of a gear train designated generally by the numeral 55.

In the operation of the tool, the eccentric shaft rotates in the concentric bearing units 49-49, about its principal axis, and the intermediate eccentric shaft portion 52 rotates therewith for reciprocating as a unit the assembly including the slide block 54, ram 26 and punch 16. It will be observed that the eccentric shaft is adequately supported at both ends thereof in the bearing units 4949 mounted respectively in the casing walls 43 and 44 on opposite sides of the ram head 28.

The intermediate eccentric shaft portion 52 is provided with a transversely extending access opening designated 56, the fore end of the shaft is slotted as at 57, and the transversely extending fore Wall 43 of the casing is provided with an access opening 58 and a removable closure member 59. In addition, the slider block 54 is provided with an access opening normal to the central aperture 53, which access opening, designated 60, communicates intermediate the opposite ends thereof with the central aperture 53.

In order to remove the punch 16 for resharpening, or for any other purpose, the closure members 48 and 59 are removed and a suitable tool is inserted through the access opening 58 for insertion into the slot 57 that is formed in the exposed end of the eccentric shaft. Then the eccentric shaft is turned to align the access opening 56 that is formed therein with the access opening 60 that is formed in the slider block and the central through bore that is formed in the ram 26. Then a suitable tool is inserted through the access openings 47, 56 and 60 and into the central through bore sections 36 and 37 for loosening and removing the set Screw 76. Now a suitable tool is inserted through access openings 61 and 62, formed respectively in the fore wall 43 of the casing and the wall of the nose part 12, for turning out the set screws 40 and 41 slightly to complete release of the punch 16, which latter is thereby freed for removal thereof through the ram 26 and the access openings 60, 56 and 47.

The steps in the operation of replacing a resharpened punch are essentially the same as just described. Of course, the sharpened punch is of shorter length than prior to sharpening and must be vertically lowered in position when replaced Within the ram in order that it descend to the proper point on a power stroke. This is accompilshed by first dropping the punch into the ram with the punch head 39 seated on the bushing annular bottom flange 75 as before. Next, a screw driver is inserted downward through the access openings 47, 56 and 60 and the blade thereof seated into the slots 73 in the bushing 70. The screw driver is then turned to screw advance the bushing 70 downward within the ram intermediate threaded central bore 37 until the punch blade 20 descends to the proper point, the screw driver being then withdrawn and the set screw 76 being inserted into the bushing 70 and tightened down on the punch head 39. Finally, the side set screws 40 and 41 are retightened against the punch flattened face 22, and the closure members 48 and 59 replaced.

It will be understood, of course, that the present invention is susceptible of various changes and modifications which may be made from time to time without dcparting from the general principle or real spirit thereof, and it is intended to claim the same broadly, as well as specifically, as indicated by the appended claims.

What is claimed as new and useful is:

1. In a motor driven sheet metal cutting tool including a vertically reciprocable punch holding ram having a vertical central bore extending therethrough which bore includes a lower portion adapted to receive a punch shank and an internally threaded upper portion of enlarged cross section relative to the lower portion, the combination comprising, an exteriorly threaded hollow cylindrical bushing open at top and bottom threaded vertically downward into the internally threaded upper portion of the ram central bore, the bushing bottom being formed by an inturned annular flange having a central opening therethrough, a punch having an elongated shank portion terminating at its bottom end in a cutting blade and terminating at its top in a head of enlarged cross-section relative to said shank, said punch shank being projected freely downward through the central opening in the bottom annular flange of said hollow bushing and said ram central bore lower portion until the punch head undersurface is seated upon the upper surface of said flange, and means coacting with said bushing to clamp said punch securely thereto, whereby said punch and bushing are constrained to reciprocate with said ram as a unit.

2. The combination according to claim 1 wherein said bushing includes means interfittable with an adjustment tool whereby said bushing may be screwed upwards and downwards as desired within the ram threaded central bore to vertically position the punch.

3. The combination according to claim 2 wherein said bushing means interfittable with an adjustment tool are slots recessed downward in the bushing wall from the top end thereof adapted to receive a screw driver blade.

4. The combination according to claim 1 wherein a portion of the exteriorly threaded bushing wall is recessed inward and accommodates therewithin a deformable insert which projects radially outward beyond the bushing exterior threads prior to insertion of the bushing into the ram and which is conformingly deformed to the ram threads when the bushing is threadedly engaged therewith, whereby the deformed insert frictionally engages the ram threads to secure the bushing against undesired rotation due to vibration when the ram is reciprocated.

5. In a motor driven sheet metal cutting tool including a vertically reciprocable punch holding ram having a vertical central bore extending therethrough which bore includes a lower portion adapted to receive a punch shank and an internally threaded upper portion of enlarged cross section relative to the lower portion, the combination comprising, an interiorly and exteriorly threaded hollow cylindrical bushing open at top and bottom threaded vertically downward into the internally threaded upper portion of the ram central bore, the bushing bottom being formed by an inturned annular flange having a central opening therethrough, a punch having an elongated shank portion terminating at its bottom end in a cutting blade and terminating at its top in a head of enlarged cross-section relative to said shank, said punch shank being projected freely downward through the central opening in the bottom annular flange of said hollow bushing and said ram central bore lower portion until the punch head undersurface is seated upon the upper surface of said flange, and a set screw exteriorly threaded complementally to the interior threading of said bushing, said set screw being screwed down into said bushing into seating engagement upon the top of said punch head to clamp said head securely between said bushing flange and said set screw, whereby said punch and bushing reciprocate with said ram as a unit.

6. The combination according ot claim 5 wherein a portion of the exteriorly threaded b ushing wall is recessed inward and accommodates therewithin a deformable insert which projects radially outward beyond the bushing exterior threads prior to insertion of the bushing into the ram and which is conformingly deformed to the ram threads when the bushing is threadedly engaged therewith, whereby the deformed insert frictionally engages the ram threads to secure the bushing against undesired rotation due to vibration when the ram is reciprocated.

7. The combination according to claim 6 wherein diametrically opposed wall portions of said bushing are slotted downward from the top end thereof to accommodate the blade of a screw driver by means of which the bushing may be screwed upwards and downwards within the ram threaded central bore to vertically position the punch.

References Cited in the file of this patent UNITED STATES PATENTS 2,272,295 Forss Feb. 10, 1942 2,278,311 Gray Mar. 31, 1942 2,376,590 Forss May 22, 1945 2,567,095 Benjamin Sept. 4, 1951 2,827,696 Yermish Mar. 25, 1958 2,844,872 Yermish July 29, 1958 

